The long-term goal of this research proposal is to characterize lipoprotein families as the fundamental physical-chemical constituents of the human plasma lipoprotein system, to determine their interrelationships, and to establish their specific functional roles in normal and deranged lipid transport processes. The purpose of the comparative studies on the chemistry of turkey and baboon plasma lipoproteins is to follow the evolution of lipid transport systems in a selected group of animals and to provide a more rational basis for their use as experimental models for investigating normal and deranged lipid transport. The specific aims of the proposed research are: 1) characterization and quantitative determination of apolipoproteins and lipoprotein families in plasma and density classes of men and women with a) normal plasma lipid concentrations, b) specific types of primary hyperlipoproteinemias, c) biliary cirrhosis, alcoholic hepatitis and obstructive gallblader disease, and d) Tangier disease, abetalipoproteinemia and glycogen storage disease; 2) utilization of the quantitative lipoprotein X test as a means for differentiating biliary atresia and neonatal hepatitis in infants; 3) determination of interrelationships between the free forms and association complexes of lipoprotein families; 4) characterization and quantification of apolipoproteins and lipoprotein families of turkey and baboon plasma and major density classes. Characterization of hypo- and hyperlipoproteinemic states by specific concentration profiles of apolipoproteins and lipoprotein families may provide a new means for identifying the underlying metabolic defects of lipid transport system and permit a more adequate classification of familial hyperlipoproteinemias based on apolipoproteins as the unique chemical markers. These studies may also provide experimental data necessary for formulating a general theory of lipid transport system.